The invention relates to an endoscope having two optical beam paths adapted for stereoscopic viewing, wherein each beam path is guided in a section in an associated optical element made of an optically transmissive material and touches an interface of the material at a point of incidence from the inside.
Such endoscopes for stereoscopic viewing are known and have proven themselves, wherein the optical beam paths are assigned to a left-hand and a right-hand viewing field for obtaining images having image depth information (3-D images).
In order to avoid light losses, if possible, in the endoscope, optical elements are frequently used which enable a reflection of the beam path without mirrors. These optical elements are made of an optically transmissive material in which the beam path is guided, wherein the beam path touches an interface of the material from the inside at a point of incidence, that is to say at the transition from the optically more dense medium to the optically less dense medium such that the beam undergoes total internal reflection. This has the advantage that the reflection behavior at the point of incidence is improved with respect to a conventional mirror. The reflection behavior can be described for example by a reflection coefficient, in particular in relation to a direction of incidence defined by the respective beam path.
In endoscopes for stereoscopic viewing, it has become customary to arrange an image recording chip in the distal region, which records images from the two optical beam paths in alternation.
In this respect it has been suggested to provide a mechanically adjustable mirror which is variable between two adjustment positions and directs the beam paths in alternation onto the image recording chip. This necessitates a great pivot path of the mirror and a complicated suspension of the mirror.